/**
 * 求两个颜色之间的渐变值
 * @param {string} startColor 开始的颜色
 * @param {string} endColor 结束的颜色
 * @param {number} step 颜色等分的份额
 * */
export const colorGradient = (startColor = 'rgb(0, 0, 0)', endColor = 'rgb(255, 255, 255)', step = 10) => {
	const startRGB = hexToRgb(startColor, false) // 转换为rgb数组模式
	const startR = Number(startRGB[0])
	const startG = Number(startRGB[1])
	const startB = Number(startRGB[2])

	const endRGB = hexToRgb(endColor, false)
	const endR = Number(endRGB[0])
	const endG = Number(endRGB[1])
	const endB = Number(endRGB[2])

	const sR = (endR - startR) / step // 总差值
	const sG = (endG - startG) / step
	const sB = (endB - startB) / step
	const colorArr:string[] = []
	for (let i = 0; i < step; i++) {
		// 计算每一步的hex值
		let hex = rgbToHex(`rgb(${Math.round((sR * i + startR))},${Math.round((sG * i + startG))},${Math.round((sB
			* i + startB))})`)
		// 确保第一个颜色值为startColor的值
		if (i === 0) hex = rgbToHex(startColor)
		// 确保最后一个颜色值为endColor的值
		if (i === step - 1) hex = rgbToHex(endColor)
		colorArr.push(hex)
	}
	return colorArr
}

// 将hex表示方式转换为rgb表示方式(这里返回rgb数组模式)
export const hexToRgb = (sColor: string, str = true) => {
	const reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/
	sColor = String(sColor).toLowerCase()
	if (sColor && reg.test(sColor)) {
		if (sColor.length === 4) {
			let sColorNew = '#'
			for (let i = 1; i < 4; i += 1) {
				sColorNew += sColor.slice(i, i + 1).concat(sColor.slice(i, i + 1))
			}
			sColor = sColorNew
		}
		// 处理六位的颜色值
		const sColorChange:number[] = []
		for (let i = 1; i < 7; i += 2) {
			sColorChange.push(parseInt(`0x${sColor.slice(i, i + 2)}`))
		}
		if (!str) {
			return sColorChange
		}
		return `rgb(${sColorChange[0]},${sColorChange[1]},${sColorChange[2]})`
	} if (/^(rgb|RGB)/.test(sColor)) {
		const arr = sColor.replace(/(?:\(|\)|rgb|RGB)*/g, '').split(',')
		return arr.map((val) => Number(val))
	}
	return sColor
}

// 将rgb表示方式转换为hex表示方式
export const rgbToHex = (rgb: string) => {
	const _this = rgb
	const reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/
	if (/^(rgb|RGB)/.test(_this)) {
		const aColor = _this.replace(/(?:\(|\)|rgb|RGB)*/g, '').split(',')
		let strHex = '#'
		for (let i = 0; i < aColor.length; i++) {
			let hex = Number(aColor[i]).toString(16)
			hex = String(hex).length == 1 ? `${0}${hex}` : hex // 保证每个rgb的值为2位
			if (hex === '0') {
				hex += hex
			}
			strHex += hex
		}
		if (strHex.length !== 7) {
			strHex = _this
		}
		return strHex
	} if (reg.test(_this)) {
		const aNum = _this.replace(/#/, '').split('')
		if (aNum.length === 6) {
			return _this
		} if (aNum.length === 3) {
			let numHex = '#'
			for (let i = 0; i < aNum.length; i += 1) {
				numHex += (aNum[i] + aNum[i])
			}
			return numHex
		}
	}
	return _this
}

/**
* JS颜色十六进制转换为rgb或rgba,返回的格式为 rgba（255，255，255，0.5）字符串
* sHex为传入的十六进制的色值
* alpha为rgba的透明度
*/
export const colorToRgba = (color: string, alpha: number | string) => {
	color = rgbToHex(color)
	// 十六进制颜色值的正则表达式
	const reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/
	/* 16进制颜色转为RGB格式 */
	let sColor = String(color).toLowerCase()
	if (sColor && reg.test(sColor)) {
		if (sColor.length === 4) {
			let sColorNew = '#'
			for (let i = 1; i < 4; i += 1) {
				sColorNew += sColor.slice(i, i + 1).concat(sColor.slice(i, i + 1))
			}
			sColor = sColorNew
		}
		// 处理六位的颜色值
		const sColorChange:number[] = []
		for (let i = 1; i < 7; i += 2) {
			sColorChange.push(parseInt(`0x${sColor.slice(i, i + 2)}`))
		}
		// return sColorChange.join(',')
		return `rgba(${sColorChange.join(',')},${alpha})`
	}

	return sColor
}

